In 30 Arkansas counties, grazing beef and dairy cattle are competing for grass against legions of armyworms.

“They’ve been reported in western Arkansas from the southwest through the Arkansas River Valley and in north central Arkansas,” said Kelly Loftin, Arkansas Extension entomologist. Loftin has fielded calls about armyworms since early August, “but they’re in a lot more counties now.”

With recent rain and greener grass, the worm numbers have skyrocketed. They can quickly devastate a pasture and other crops if left untreated. The Arkansas Extension Service recommends treating for armyworms if there are three or more adult worms per square foot.

“Most of the people I’ve heard from are finding much higher than threshold numbers, as much as 20 or more,” Loftin said. The Extension Service recommends that producers treat for armyworms if adult numbers reach three or more per square foot.

“If they’re small you have a little time,” Loftin noted, but the larger they are the less time you have before they become an economic threat.

Before treating the insects, producers should read product labels for information about grazing withdrawal.

With Sevin, producers can’t graze cattle on treated pastures for two weeks, but with Tracer, producers only need to wait for pastures to dry after treatment to reintroduce cattle.

The entomologist recommends that producers scout their fields regularly through the end of September.

For more information and updates, contact your county Extension agent or go to http://www.uaex.edu and select Agriculture, Newsletters and Pest Management News.